A brain cyst load-associated antigen is a Toxoplasma gondii biomarker for serodetection of persistent parasites and chronic infection

Abstract Background Biomarker discovery remains a major challenge for predictive medicine, in particular, in the context of chronic diseases. This is true for the widespread protozoan Toxoplasma gondii which establishes long-lasting parasitism in metazoans, humans included. This microbe successively unfolds distinct genetic programs that direct the transition from high to low replicative potential inside host cells. As a slow-replicating cell, the T. gondii bradyzoite developmental stage persists enclosed in a cyst compartment within tissues including the nervous system, being held by a sustained immune equilibrium which accounts for the prolonged clinically silent phase of parasitism. Serological surveys indicate that nearly one third of the human population has been exposed to T. gondii and possibly host bradyzoites. Because any disruption of the immune balance drives the reverse transition from bradyzoite to fast replicating tachyzoite and uncontrolled growth of the latter, these people are at risk for life-threatening disease. While serological tests for discriminating recent from past infection are available, there is yet no immunogenic biomarker used in the serological test to allow ascertaining the presence of persistent bradyzoites. Results Capitalizing on genetically engineered parasites induced to produce mature bradyzoites in vitro, we have identified the BCLA/MAG2 protein being restricted to the bradyzoite and the cyst envelope. Using laboratory mice as relevant T. gondii host models, we demonstrated that BCLA/MAG2 drives the generation of antibodies that recognize bradyzoite and the enveloping cyst structure. We have designed an ELISA assay based on a bacterially produced BCLA recombinant polypeptide, which was validated using a large collection of sera from mice of different genetic backgrounds and infected with bcla+ or bcla-null cystogenic and non-cystogenic T. gondii strains. To refine the design of the ELISA assay, we applied high-resolution BCLA epitope mapping and identified a specific combination of peptides and accordingly set up a selective and sensitive ELISA assay which allowed the detection of anti-BCLA/MAG2 antibodies in the sera of human patients with various forms of toxoplasmosis. Conclusions We brought proof of principle that anti-BCLA/MAG2 antibodies serve as specific and sensitive serological markers in the perspective of a combinatorial strategy for detection of persistent T. gondii parasitism.

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AMA1-Deficient Toxoplasma gondii Parasites Transiently Colonize Mice and Trigger an Innate Immune Response That Leads to Long-Lasting Protective Immunity

Infection and Immunity ◽

10.1128/iai.02606-14 ◽

2015 ◽

Vol 83 (6) ◽

pp. 2475-2486 ◽

Cited By ~ 14

Author(s):

Vanessa Lagal ◽

Márcia Dinis ◽

Dominique Cannella ◽

Daniel Bargieri ◽

Virginie Gonzalez ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Distinct Type ◽

Genetically Engineered ◽

Host Cells ◽

Type I ◽

Content Type ◽

Apical Membrane Antigen 1 ◽

Immunocompromised Mice

The apical membrane antigen 1 (AMA1) protein was believed to be essential for the perpetuation of two Apicomplexa parasite genera,PlasmodiumandToxoplasma, until we genetically engineered viable parasites lackingAMA1. The reduction in invasiveness of theToxoplasma gondiiRH-AMA1 knockout (RH-AMA1KO) tachyzoite population,in vitro, raised key questions about the outcome associated with these tachyzoites once inoculated in the peritoneal cavity of mice. In this study, we used AMNIS technology to simultaneously quantify and image the parasitic process driven by AMA1KOtachyzoites. We report their ability to colonize and multiply in mesothelial cells and in both resident and recruited leukocytes. While the RH-AMA1KOpopulation amplification is rapidly lethal in immunocompromised mice, it is controlled in immunocompetent hosts, where immune cells in combination sense parasites and secrete proinflammatory cytokines. This innate response further leads to a long-lasting status immunoprotective against a secondary challenge by high inocula of the homologous type I or a distinct type IIT. gondiigenotypes. While AMA1 is definitively not an essential protein for tachyzoite entry and multiplication in host cells, it clearly assists the expansion of parasite populationin vivo.

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Serological diagnosis of Toxoplasma gondii: analysis of false-positive IgG results and implications

Parasite ◽

10.1051/parasite/2020006 ◽

2020 ◽

Vol 27 ◽

pp. 7 ◽

Cited By ~ 1

Author(s):

Loïc Simon ◽

Judith Fillaux ◽

Aurélie Guigon ◽

Rose-Anne Lavergne ◽

Odile Villard ◽

...

Keyword(s):

Toxoplasma Gondii ◽

False Positive ◽

Primary Infection ◽

Preventive Measures ◽

Neospora Caninum ◽

Confirmatory Test ◽

Serological Tests ◽

Past Infection ◽

Recombinant Antigens ◽

False Positivity

Background: Primary infection by Toxoplasma gondii in pregnant women can result in serious outcomes for the foetus. A false-positive IgG result during pregnancy can lead to a misdiagnosis of past infection and to stopping preventive measures. We collected 189 sera with positive Architect® Toxo IgG assay (Abbott Laboratories) and negative IgG results with at least two other serological tests, in order to find an explanation for the suspected false-positive IgG results. We used the recomLine Toxoplasma IgG® immunoblot (Mikrogen Diagnostik) to search for specific antigenic reactivities of the sera, and the LDBio Toxo II IgG® immunoblot (LDBio Diagnostics) as a confirmatory test. Results: The bands GRA8 and/or GRA7 were positive for 148 samples (78.3%). GRA8 was the most frequent band, appearing in 133 patterns (70.4%), whereas GRA7 was present for 49 samples (25.9%). Of the 81 samples tested with LDBio®, 23 (28.4%) turned out to be positive. Of the 58 negative LDBio® tests (71.6%) (real false-positive Architect® IgG), 23 samples (39.6%) did not show either a GRA8 or p30 band by recomLine®. Their false positivity with Architect® remains unexplained since Abbott uses these two recombinant antigens for their assay. Conclusions: The Architect® IgG false positivity for T. gondii seems to be due to reactivity against GRA8 for the majority of the sera and GRA7 to a lesser extent. The hypothesis of past contact with parasites genetically close to T. gondii such as Hammondia hammondi or Neospora caninum seems promising and should be assessed further.

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First report on qualitative detection of anti-COVID-19 antibody IgM and IgG in a short series of 98 subjects, healthcare workers and patients, by use an ELISA assay

Working Paper of Public Health ◽

10.4081/wpph.2020.9230 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

A. Roveta ◽

M. Cassinari ◽

R. Guaschino ◽

T. Callegari ◽

L. Mazzucco ◽

...

Keyword(s):

Healthcare Workers ◽

Serological Test ◽

Elisa Assay ◽

Technological Evolution ◽

Rt Pcr ◽

Serological Tests ◽

Short Series ◽

Current State ◽

Qualitative Detection ◽

Previous Contact

Objective: The aim is to perform a preliminary testing about the presence of anti-COVID-19 IgM and IgG in a short series of healthcare workers and patients at SS. Antonio e Biagio e Cesare Arrigo Hospital, in Alessandria. Methods: Healthcare workers voluntarily agreed to perform the analysis. For patients, serological test was performed at clinician’s discretion. Detection of anti-COVID-19 IgM and IgG was performed separately by use ELISA assay. In order to perform a comparison age, sex, onset symptoms, RT-PCR result were collected. Results: Serological findings showed that most people with positive SARS-CoV-2 RT-PCR testing developed anti-SARS-CoV-2 IgG 14 days after the date of rhinopharyngeal swab and that anti-SARS-CoV-2 IgG detection was also observed in patients with negative RT-PCR. No anti-SARS-CoV-2 IgM was found. Conclusions: Serological testing may be useful to confirm a previous contact with SARS-CoV-2, but it cannot be used in diagnostics. They need further evidence on its performance and operational utility. At the current state of technological evolution, SARS-CoV-2 IgM and IgG antibodies serological tests can be used to supplement the viral RNA detenction by use RT-PCR.

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Toxoplasma Gondii Bradyzoites Elicit Transcriptional Changes in Host Cells to Prevent IFNγ-Mediated Cell Death

SSRN Electronic Journal ◽

10.2139/ssrn.3316792 ◽

2019 ◽

Author(s):

Simona Seizova ◽

Alexandra L Garnham ◽

Michael J Coffey ◽

Lachlan W Whitehead ◽

Kelly L Rogers ◽

...

Keyword(s):

Cell Death ◽

Toxoplasma Gondii ◽

Host Cells ◽

Transcriptional Changes

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Toxoplasma gondii Parasites Take Control within Host Cells

Microbe Magazine ◽

10.1128/microbe.7.360.1 ◽

2012 ◽

Vol 7 (8) ◽

pp. 360-365

Author(s):

Eric Y. Denkers ◽

Barbara A. Butcher

Keyword(s):

Toxoplasma Gondii ◽

Host Cells

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Releasing latent Toxoplasma gondii cysts from host cells to the extracellular environment induces excystation

International Journal for Parasitology ◽

10.1016/j.ijpara.2021.04.004 ◽

2021 ◽

Author(s):

Taizo Saito ◽

Tatsunori Masatani ◽

Katsuya Kitoh ◽

Yasuhiro Takashima

Keyword(s):

Toxoplasma Gondii ◽

Host Cells ◽

Extracellular Environment

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Seropositivity to canine tick-borne pathogens in a population of sick dogs in Italy

Parasites & Vectors ◽

10.1186/s13071-021-04772-9 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Jairo Alfonso Mendoza-Roldan ◽

Giovanni Benelli ◽

Marcos Antonio Bezerra-Santos ◽

Viet-Linh Nguyen ◽

Giuseppe Conte ◽

...

Keyword(s):

Borrelia Burgdorferi ◽

Serological Test ◽

Control Strategies ◽

Central Italy ◽

Rickettsia Conorii ◽

High Seroprevalence ◽

The South ◽

Serum Samples ◽

Serological Tests ◽

Distribution Maps

Abstract Background Canine vector-borne diseases (CVBDs) associated to ticks are among the most important health issues affecting dogs. In Italy, Ehrlichia canis, Anaplasma spp., Rickettsia conorii and Borrelia burgdorferi (s.l.) have been studied in both healthy canine populations and those clinically ill with suspected CVBDs. However, little information is currently available on the overall prevalence and distribution of these pathogens in the country. The aim of this study was to assess the prevalence and distribution of tick-borne pathogens (TBPs) in clinically suspect dogs from three Italian macro areas during a 15-year period (2006–2020). Methods A large dataset (n = 21,992) of serological test results for selected TBPs in three macro areas in Italy was analysed using a Chi-square test to evaluate the associations between the categorical factors (i.e. macro area, region, year, sex and age) and a standard logistic regression model (significance set at P = 0.05). Serological data were presented as annual and cumulative prevalence, and distribution maps of cumulative positive cases for TBPs were generated. Results Of the tested serum samples, 86.9% originated from northern (43.9%) and central (43%) Italy. The majority of the tests was requested for the diagnosis of E. canis (47%; n = 10,334), followed by Rickettsia spp. (35.1%; n = 7725), B. burgdorferi (s.l.) (11.6%; n = 2560) and Anaplasma spp. (6.2%; n = 1373). The highest serological exposure was recorded for B. burgdorferi (s.l.) (83.5%), followed by Rickettsia spp. (64.9%), Anaplasma spp. (39.8%) and E. canis (28.7%). The highest number of cumulative cases of Borrelia burgdorferi (s.l.) was recorded in samples from Tuscany, central Italy. Rickettsia spp. was more prevalent in the south and on the islands, particularly in dogs on Sicily older than 6 years, whereas Anaplasma spp. was more prevalent in the north and E. canis more prevalent in the south and on the islands. Conclusions The results of this study highlight the high seroprevalence and wide distribution of the four TBPs in dogs with clinically suspected CVBDs from the studied regions of Italy. The very high seroprevalence of B. burgdorferi (s.l.) exemplifies a limitation of this study, given the use of clinically suspect dogs and the possibility of cross-reactions when using serological tests. The present research provides updated and illustrative information on the seroprevalence and distribution of four key TBPs, and advocates for integrative control strategies for their prevention. Grapic abstract

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Loss of a conserved MAPK causes catastrophic failure in assembly of a specialized cilium-like structure in Toxoplasma gondii

Molecular Biology of the Cell ◽

10.1091/mbc.e19-11-0607 ◽

2020 ◽

Vol 31 (9) ◽

pp. 881-888 ◽

Cited By ~ 6

Author(s):

William J. O’Shaughnessy ◽

Xiaoyu Hu ◽

Tsebaot Beraki ◽

Matthew McDougal ◽

Michael L. Reese

Keyword(s):

Toxoplasma Gondii ◽

Host Cells ◽

Ultrastructural Changes ◽

Catastrophic Failure ◽

Replicative Cycle

Toxoplasma gondii that lacks the kinase ERK7 cannot invade or egress from their host cells, thereby blocking their replicative cycle. These defects are due to the loss of a specialized cilium-like structure called the conoid. Strikingly, the ultrastructural changes are specific to the conoid, and suggest an important role for ERK7 in its biogenesis.

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Occurrence of antibodies against Neospora caninum and/or Toxoplasma gondii in dogs with neurological signs

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612011000300004 ◽

2011 ◽

Vol 20 (3) ◽

pp. 202-206 ◽

Cited By ~ 8

Author(s):

Nicolle Fridlund Plugge ◽

Fabiano Montiani Ferreira ◽

Rosária Regina Tesoni de Barros Richartz ◽

Adriana de Siqueira ◽

Rosangela Locatelli Dittrich

Keyword(s):

Toxoplasma Gondii ◽

Neospora Caninum ◽

Neurological Diseases ◽

Fluorescent Antibody ◽

Antibody Test ◽

Metropolitan Region ◽

Serological Tests ◽

Stray Dogs ◽

Neurological Signs ◽

Significant Difference

This study aimed to evaluate occurrences of antibodies against Neospora caninum and Toxoplasma gondii in dogs with neurological signs. Blood samples from 147 dogs were collected: 127 from owned dogs (attended at the Veterinary Teaching Hospital of the Federal University of Paraná (HV-UFPR) and at private veterinary clinics in the city of Curitiba), and 20 from stray dogs found in Curitiba's metropolitan region. The dogs presented one or more of the following neurological signs: seizures, paresis or paralysis, ataxia, behavioral abnormalities, sensory and somatic disorders and chorioretinitis. The samples were analyzed by means of the indirect fluorescent antibody test (IFAT), at a cutoff dilution of 1:50. Out of the 147 samples obtained, 17 (11.56%) were seropositive for N. caninum, 31 (21.08%) for T. gondii and four (2.72%) for both protozoa. Serum titration on the positive animals showed that 54.83% (17/31) and 41.18% (7/17) had titers > 1:200 against T. gondii and N. caninum, respectively. A significant difference in seropositivity for T. gondii (P = 0.021; OR = 2.87; CI = 1.1 > 2.8 > 7.4) was observed between owned dogs (18.11%) and stray dogs (40%). Inclusion of serological tests for neosporosis and toxoplasmosis is recommended in diagnosing neurological diseases in dogs.

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